//This function takes in latitude and longitude of two location and returns the distance between them as the crow flies (in km)
function CoordDistance(lat1: number, lon1: number, lat2: number, lon2: number) {
  const R = 6371 // km
  const dLat = toRad(lat2 - lat1)
  const dLon = toRad(lon2 - lon1)
  const lat1_calc = toRad(lat1)
  const lat2_calc = toRad(lat2)

  const a =
    Math.sin(dLat / 2) * Math.sin(dLat / 2) +
    Math.sin(dLon / 2) *
      Math.sin(dLon / 2) *
      Math.cos(lat1_calc) *
      Math.cos(lat2_calc)
  const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a))
  const d = R * c
  return d
}

// Converts numeric degrees to radians
function toRad(value: number) {
  return (value * Math.PI) / 180
}

export function handleDistanceCoord(
  lat1: number,
  lon1: number,
  lat2: number,
  lon2: number,
) {
  const distance = CoordDistance(lat1, lon1, lat2, lon2)
  if (distance < 1) {
    return `~${Math.round(distance * 1000)} m`
  }
  return `~${Math.round(distance)} km`
}